Carburetor metering adjustment



Dec. 13, 1960 R. J. SMITH ET AL 2,964,303

CARBURETOR METERING ADJUSTMENT Filed Aug. 21, 1958 2 Sheets-Sheet 1INVENTORS ROBERT J. SMITH BY WILLIAM F. OTT

AT,TORNEY Dec. 13, 1960 R. J. SMITH' ETAL CARBURETOR METERING ADJUSTMENTFiled Aug. 21, 1958 2 Sheets-Sheet 2 I NVENTORS ROBERT. J; SMITH BYWILLIAM F. OTT

ATTORNEY manufacture.

'CARBURETOR METERING ADJUSTMENT Robert J. Smith, St. Anns, and WilliamF. on, Atrton, Mo., assignors to ACF Industries, Incorporated, New York,N.Y., a corporation of New Jersey Filed Aug. 21, 1958, Ser. No. 756,340

19 Claims. (Cl. 261-51) This invention relates to carburetors forinternal combustion engines, especially of the automotive type, and moreparticularly to carburetors of the type in which fuel supplied from thefloat bowl of the carburetor to a nozzle of the carburetor is metered bymeans of a metering rod extending through a metering orifice, the rodbeing movable to vary the effective sizeof the orifice and to controlthe flow of.fuel from the bowl to the nozzle.

In certain carburetors of the class described, the metering rod isoperated by means of a linkage from the throttle shaft of thecarburetor. For proper metering, provision must be made for adjustmentof the metering rod relative tothe throttle shaft so that the rod willoccupy appropriate positions for various degrees of opening of thethrottle valve including the usual slightly open dead idle position.Among the several objects of this invention may be noted the provisionof a construction which simplifies the operation of adjusting themetering rod relative to the throttle shaft, allowing for suchadjustment by the simple act of moving the throttle valve to fullyclosed position, without any necessity for any additional operations;and the provision of a construction having the stated characteristicswhich is economical to In general, these objectsv are attained byproviding a lost-motion friction connection in the linkage between thethrottle shaft and the metering rod, this connection permitting relativeadjusting movement between the parts connected thereby and adaptedfrictionally to retain the parts in any position to which they may beadjusted. With this lost-motion friction connection in the linkage,adjustment may be accomplished by moving the throttle valve to fullyclosed position, with accompanying movement of the metering rod in onedirection to its limit of movement in that direction during the initialphase of movement of the throttle valve, and with relative adjustingmovement of the parts during completion of'movement of the throttlevalve. Another object of the invention is the provision of a lost-motionfrictional connection invention is incorporated;

, Fig. 2 is an enlarged vertical section taken on lines 2-2 of Figs. 1and 3;

Fig. 3 is a vertical section taken on line 33 of Fig. 2; Fig. 4 is aview similar to Fig. 2 illustrating a modification, being in section online 5-5 of Fig. 4;

Fig. 5 is a vertical section taken on line 55 of Fig. 4; Figs. 6-9 areviews similar to Fig. 2 illustrating addinite tates Patent tionalmodifications, Fig. 9 being in section on line 9--9 of Fig. 10; and,

Fig. 10 is a vertical section taken on line 10-10 of Fig. 9.Corresponding reference characters indicate corresponding partsthroughout the several views of the drawmgs. Referring to Fig. 1 of thedrawings, there is indicated at 1 a carburetor comprising a body 3formed to provide a mixture conduit 5 and a fuel bowl 7. A fuel bowlcover is indicated at 9. This is formed to provide an air horn 11 forconduit 5. The upper portion of mixing conduit Sis formed as a venturi,as indicated at 13, and below this is the throttle bore 15. In thethrottle bore'is a throttle valve 17, which is fixed on throttle shaft19. Fixed on one end of throttle shaft 19 is a bell crank 21. Connectedto one arm 21a of bell crank 21 is an actuating rod 23, which isoperated by the usual pedal. A spring such as indicated at 25 connectedto rod 23 acts to bias the throttle valve in closing direction(counterclockwise as viewed in Fig. 1). Movement of throttle valve 17 inclosing direction is limited by a stop screw 27 adjustably threaded in alug 29 on the mixture conduit "part of the carburetor engageable by bellcrank 21.

Screw 27 normally occupies a position determining a slightly open idlingposition of throttle valve 17. Screw 27 is adapted to be backed off toallow the throttle valve completely to close.

The carburetor body 3 is formed. with a vertical accelerator pumpcylinder 31. A piston 33 is slidable in cylinder 31. A lever 35 ispivoted intermediate its ends as indicated at 37 on top of the cover 9for rocking movement on-a horizontal axis. A rod 39 connects one end oflever 35 and piston 33. A bendable link 41 connects arm 21b of hellcrank 21 to the other end of lever 35, the. arrangement being such thatupon opening throttle valve 17, piston 33 is driven down through adischarge stroke, and on closing the throttle valve the piston is pulledup through a charging stroke. A checkvalved inlet for flow of fuel frombowl 7 to pump cylinder31 is indicated at 42; an outlet for exit of fuelfrom the pump cylinder is indicated at 43. Outlet 43 connects to apassage 45 leading to the mixture conduit.

'T he carburetor has a fuel nozzle 47 extending into the mixture conduitfrom a high speed fuel passage 49. This passage includes a well 51 atthe bottom of the fuel bowl. At the upper end of the well (the entranceto the passage from the bowl) is a metering orifice member 53 in whichthere is a metering orifice 55. Extending down through the fuel bowl andhaving its lower end portion extending through the metering orifice 55is a metering rod 57. As shown, this rod is a three-step rod, the stepsbeing designated 59, 61 and 63, the middle step 61 being a tapered step,but it will be understood that rods with other step formations may beused. The rod extends up out of the fuel bowl through a hole 65 in cover9 and has its upper end connected to lever 35 by a special connection ofthis invention indicated at 67.

Connection 67 is a lost-motion frictional connection. As shown in Figs.2 and 3, it includes a bearing constituted by a grommet 69 having atubular stem 71 slidable in an elongate slot 73 in the lever 35. Slot 73is located between pivot 37 of lever 35 and the point where link 41 isconnected to the lever, and is preferably an arcuate slot curved on anare centered in the axis of pivot 37. The metering rod 57, at its upperend, has a portion bent to provide an arm 75 extending at right anglesfrom the rod and received in the grommet. The grommet has a head 77 atone end engaging one side of the lever and a cupped circular springwasher 79 secured at its other end engaging the other side of the lever.Washer 79 holds head 77 in frictional en:

gagernent with the lever and is itself in frictional engagement with thelever. Washer 79 is formed with a spring tail 81, the end of which isreceived in an annular groove 83 adjacent the end of arm 75 of themetering rod. Tail '81 serves two purposes: first, to retain arm 75-ofthe metering rod in the grommet; second, to bias the metering rodlaterally and hold it against one side of the orifice 55 (see Fig. 2).The grommet 69 is slidable in slot 73 in lever 35 between limitingpositions determined by engagement of its stem 71 with the ends .of theslot, and is frictionally retained in any position to which it mayslide. Arm 75 of the metering rod is rotatable in the grommet to allowfor swinging of lever 35 without bending the metering rod and axiallyslidable in the grommet to allow spring tail 81 to bias the metering rodlaterally.

Adjustment of the above-described construction isconveniently carriedout by first bending link '41 to obtain the proper stroke of pump piston33. Then, with the throttle valve 17 open, the metering rod 57 is moveddownward relative to lever 35 to bring the grommet 69 to the lower endof the slot 73. Screw 27 'is backed oif to permit the throttle valve 17to be moved to a fullyclosed position in throttle bore (as distinguishedfrom its normal slightly open dead idle position), and the throttlevalve is thenmoved to the fully closed position. This swings lever 35clockwise as viewed in Fig. l, and drives the metering rod 57 downward.The rod moves downward until its lower end engages the bottom of thewell 51, which serves as means for limiting the downward movement forthe rod. This occurs before the throttle valve is fully closed. As thethrottle valve completes its movement to fully closed position, withaccompanying further clockwise swinging of lever 35, the lever 35 swingsdown relative to the grommet 69, and the latter is in effect raised inthe slot 73 and repositioned in the slot at the proper setting forholding the metering rod properly positioned relative to the throttleshaft. Finally, the screw 27 is turned to bring it back into positionfor determining the dead idle position of the throttle valve. As aresult, when the throttle valve is in its slightly open dead idleposition (see Fig. l), the lower end of the metering rod is raised fromthe bottom of well 51 and in proper position for metering fuel at idle(see Figs. 1-3), and as the throttle valve is opened, the metering rodis moved along with the throttle valve to appropriate positions forvarious degrees of opening of the throttle valve.

Figs. 4and 5 illustrate a modification of the lost-motion frictionalconnection, in which there is a pin 85 (instead of grommet 69) slidablein the slot 73 in the lever 35. The metering rod 57, instead of beingformed with a lateral arm at its upper end, is formed with an eye 87"receiving the pin 85. The pin has a head 91 at one end engaging oneside of the lever 35. A spring fastener 93 retained in an annular groove95 in the pin engages the other side of the lever 35. Fastener 93 holdshead 91 in frictional engagement with the stated one side of the leverand is itself in frictional engagement with the other 'side of thelever. The eye 87 of the metering rod 57 is held on the pin by means ofa washer 97 and a spring clip such as indicated at 99 received in anannular groove 101 adjacent the end of the pin. The eye 87 of themeterjing rod 57 has some axial play on the pin, andis biased outwardaway from the lever 35 for engagement of the ro'd'with one side of theorifice 55 by means of a spring tail 103 formed integrally with thespring fastener 93.

Fig. 6 illustrates another possible modification of the lost-motionfrictional connection which is similar to the construction shown in Fig..2, except that the spring tail "81'is omitted from washer 79, and thearm 75 of the metering rod 57 is biased axially by means of a coilspring 105 surrounding the .arm and reacting-from the grommet 69 againsta collar -107 on the'end of arm 75.

Fig. 7 illustrates another, possible modification of :the

lost-motion frictional connection in which the arm 75 of the meteringrod extends through the slot 73 in the lever 35 without any grommet,being retained in assembly with the lever by means of a U-shaped springclip 109 straddling the lever and in frictional engagement with oppositesides of the lever, and having a portion 111 on one side (which may bemade like fastener 93 in Fig. 5) received in an annular groove 113adjacent the end of arm 75 of the rod acting to hold the rod inengagement with one side of the orifice 55.

Fig. 8 illustrates another modification in which a spring washer 115 isinterposed between the head 77a of the grommet 69a and the adjacent sideof the lever. The stem of the grommet is threaded as indicated at 117,and a frictional washer 119 is applied to the stem of the grommetengaging the other side of the lever, a nut 121 being threaded on thestem backing up the frictional washer 119. The arm 75 of the meteringrod 57 is retained in assembly with the grommet 69a by means of a collar122. Arm 75 is axially slidable in the grommet, and is biased toward theleft as viewed in Fig. 8 by a spring tail 123 on the spring washer 115.

Figs. 9 and 10 illustrate another modification in which, instead ofhaving a slot like slot 73 in me lever 35, there is a pin 125 rotatablycarried by the lever. Pin 125 has a reduced end portion 127 received ina hole 129 in the lever, being retained in assembly with the lever bymeans of a washer 131 secured on the reduced end portion of the pin.There is sufiicient looseness between the pin, the washer and the leverthat the pin may rotate freely in the hole. The pin has a transverseopening 133, and the upper end of the metering rod 57 extends throughthis opening, being slidable therein. A spring ring 135 is secured in arecess -137 in the pin surrounding the upper end of the metering rod andin frictional engagement therewith. 'A coil spring 139 surrounds thepin, having one end secured as indicated at 141 to the pin and having anextending end portion 143 engaging the metering rod 57 and biasing themetering rod to swing laterally into engagement with one side of theorifice 55.

In view of the above, it will be seen that the several objects of theinvention are achieved and other advantageous results attained.

As various changes could be made in the above constructions withoutdeparting from the scope of the invention, it is intended that allmatter contained in the above description or shown in the accompanyingdrawings shall be interpreted as illustrative and not in a limitingsense.

We claim:

1. In a carburetor having a mixture conduit, a throttle valve in saidconduit, a fuel bowl, a nozzle, a passage from the fuel bowl tothenozzle having a metering orifice therein, a metering rod movable in theorifice, a linkage connecting the valve and rod for moving the rod inone direction on movement of the valve in closing direction and in theother direction on movement of the valve in opening direction, and meansfor limiting movement of the rod in said one direction, said linkageincluding a lost-motion friction connection permitting relativeadjusting movement between the parts connected thereby and adaptedfrictionally to retain the parts in any position to which they may beadjusted, whereby the linkage may be adjusted by moving the valve tofully closed position with accompanying movement of the rod in said onedirection to its limit of movement during the initial phase of movementof the valve and with relative adjusting movement of said parts duringthe completion of movement of the valve.

2. In a carburetor as set forth in claim 1, one of said parts having anopening therein and the other of said parts having a portion slidable insaid opening, and means connected with one'of said parts andfrictionally engaging the other of said parts.

3. In a carburetor as set forth in claim 1, one of said partsehaving anelongate slot therein and the other of said parts having a portionslidable in said slot from one end thereof to the other, and springmeans connected with one of said parts and frictionally engaging theother of said parts for providing a driving connection between saidparts.

4. In a carburetor having a mixture conduit, a throttle valve in saidconduit, a fuel bowl, a nozzle, a passage from the fuel bowl to thenozzle having a metering orifice therein, a metering rod movable in theorifice, a linkage connecting the valve and rod for moving the rod inone direction on movement of the valve in closing direction and in theother direction on movement of the valve in opening direction, and meansfor limiting movement of the rod in said one direction, a lost-motionfriction connection between an element of said linkage and said rodpermitting relative adjusting movement between the rod and said elementand adapted frictionally to retain the rod in any position to which itmay be adjusted relative to said element, whereby the rod may beadjusted by moving the valve to fully closed position with accompanyingmovement of the rod in said one direction to its limit of movementduring the initial phase of movement of the valve and with relativeadjusting movement of said rod and said element during the completion ofmovement of the valve.

5. In a carburetor as set forth in claim 4, said connection includingspring means acting to bias the rod laterally into engagement with oneside of said orifice.

6. In a carburetor as set forth in claim 4, said connection including asingle spring means for providing friction for the connection and alsoacting to bias the rod laterally into engagement with one side of saidorifice.

7. In a carburetor having a mixture conduit, a throttle valve in saidconduit, a fuel bowl, a nozzle, a passage from the fuel bowl to thenozzle having a metering orifice therein, a metering rod movable in theorifice, a lever, a link connecting the throttle valve and lever, astmotion friction connection between the metering rod and lever, the rodbeing movable in one direction on movement of the valve in closingdirection and in the other direction on movement of the valve in openingdisection, and means for limiting movement of the rod in said onedirection, said lost-motion friction connection permitting relativeadjusting movement between the rod and lever and adapted frictionally toretain the rod in any position to which it may be adjusted relative tothe lever, whereby the rod may be adjusted by moving the valve to fullyclosed position with accompanying movement of the rod in said onedirection to its limit of movement during the initial phase of movementof the valve and with relative adjusting movement of said rod and leverduring the completion of movement of the valve.

8. In a carburetor as set forth in claim 7, the lever having an openingtherein and the rod having a part slidable in the opening, and means forproviding friction between the lever and said part of the rod.

9. In a carburetor as set forth in claim 7, the lever having an elongateslot therein, the rod having a lateral arm slidable in said slot fromone end thereof to the other, and spring means for providing frictionbetween said arm and said lever.

10. In a carburetor as set forth in claim 9, said spring means alsoacting to bias the rod laterally into engagement with one side of saidorifice.

11. In a carburetor as set forth in claim 7, the lever having anelongate slot therein, a grommet slidable in the slot from one endthereof to the other, the rod having an end portion bent to provide alateral arm, said arm being rotatable and slidable in the grommet, saidgrommet having a head at one end engaging one side of the lever, and aspring washer at its other end engaging the other side of the lever.

12. In a carburetor as set forth in claim 11, spring means biasing saidarm axially in one direction in the grommet to bias the rod laterallyinto engagement with one side of the orifice.

13. 'In a carburetor as set forth in claim 12, said spring means beingan integral part of said spring washer.

14. In a carburetor as set forth in claim 7, the lever having anelongate slot therein, a pin slidable in the slot from one end thereofto the other, the rod having an eye receiving the pin, the pin having ahead at one end engaging one side of the lever, and a spring washer onthe pin engaging the other side of the lever and acting to bias the pinaxially in the direction for frictional engagement of the head with saidone side of the lever.

15. In a carburetor as set forth in claim 14, said eye being slidable onthe pin, and said washer having a tail acting to bias the rod laterallyinto engagement with one side of the orifice.

16. In a carburetor as set forth in claim 7, the lever having anelongate slot therein, the rod having an end portion bent (to provide alateral arm, said arm extending through the slot and being slidabletherein from one end thereof to the other, and a U-shaped spring memberreceiving the arm straddling the lever and in frictional engagementtherewith.

17. In a carburetor as set forth in claim 7, the lever having anelongate slot therein, a grommet slidable in the slot from one endthereof to the other, the rod having an end portion bent to provide alateral arm, said arm being rotatable and slidable in the grommet, saidgrommet having a head at one end, a spring washer between said head andone side of the lever, a friction washer on the grommet engaging theother side of the lever, and said spring washer having a tail acting tobias the rod laterally into engagement with one side of the orifice.

18. In a carburetor as set forth in claim 7, said connection comprisinga pin rotatably carried by the lever, said pin having a transverseopening, said rod having an end portion slidable in said opening, andmeans carried by the pin in frictional engagement with the rod.

19. In a carburetor as set forth in claim 18, spring means secured tothe pin and biasing the rod to swing on the axis of the pin to hold therod in engagement with one side of said orifice.

2,711,885 Moseley et al. June 28, 1955

